Adding an effect on a project

Is there a way of putting an effect on the stage so it's constantly there, ie I have 20 scenes finished consisting of transparent PNG's, and movie files, but I would like to add a texture like an old movie scratch on them all, so it's there all the time, is this possible? or do I have to implement it in the 20 scenes one by one?

does the Projector for each scene have the same settings? if so, you can replace each Projector with a Broadcaster, and place a Listener, your desired texture effect, and a Projector in a separate scene, and activate this so that it remains active as you pass through each of the other scenes.

If you had used a user actor with a projector inside it you could have done this. Crappy I know to offer this, but if you are making similar scenes over and over user actor are the way to go. This way when you want to change them all you only have to change one.